Ultima Thule

In ancient times the northernmost region of the habitable world - hence, any distant, unknown or mysterious land.

Tuesday, November 07, 2006


By Aussiegirlt

Tomorrow, Wednesday, beginning at 2:12 p.m. and lasting about 5 hours, Mercury begins its transit across the face of the Sun. I already posted an article about this about 3 weeks ago, but you may have missed it, so here is the link: 2006 Transit of Mercury -- by the way, you'll find in the article a really neat animation of the transit that shows a tiny black dot moving across a larger yellow Sun, so be sure to click on it -- and when you're watching the real thing tomorrow, try not to blind yourself, lest you can't read my blog anymore!

And here is the description from Wikipedia's article:

A transit of Mercury across the Sun takes place when the planet Mercury comes between the Sun and the Earth, and Mercury is seen as a small black dot moving across the face of the Sun.

Transits of Mercury with respect to Earth are much more frequent than transits of Venus, with about 13 or 14 per century, in part because Mercury is closer to the Sun and orbits it faster.

Transits of Mercury can happen in May or November. November transits occur at intervals of 7, 13, or 33 years; May transits only occur at intervals of 13 or 33 years. The last two transits were in 1999 and 2003; the next two will occur in 2006 and 2016.

During a May transit, Mercury is near aphelion and has an angular diameter of 12"; during a November transit, it is near perihelion and has an angular diameter of 10".


Here's an update from today's The Maui Times:

Mercury’s rare trip across face of sun to be webcast

HALEAKALA – A webcast of a rare astronomical event will be transmitted live from observatories on the summits of Haleakala and Mauna Kea beginning at 9:12 a.m. Wednesday, the University of Hawaii Institute for Astronomy has announced.

The event is a transit of Mercury across the face of the sun. The webcast will include discussions by astronomers of the observations of the tiny black dot passing across the face of the sun.

During the five-hour transit, no one should attempt to look directly at the sun, which can cause severe damage to unprotected eyes. Astronomers at the two observatory sites will be using special telescopes to record the event in a variety of wavelengths of light.

For the webcast, go here.

For information on the Mercury transit, go online to the Institute for Astronomy site at www.ifa.hawaii.edu, or to the site for the National Solar & Heliospheric Observatory at http://sohowww.nascom.nasa.gov.


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